Centrifugal separator



Aug. v7, 1934.

H. O. LINDGREN CENTRIFUGAL sEPARAToR Filed Sept. 18. 1951 2 Sheets-Sheet 1 y/rA/fss.- www.

Aug' 7 1934' H. o. LINDGREN CENTRIFUGAL SEPARATQR 2 Sheets-Shes?.` 2

Filed Sept. l18.l 1931 y /IV Vf' /V 7' l? //an s OL/of zlzalyrezz W/T/VESS.'

Patented Ang. 7, 1934l iaeaaze cenrannaar. sarana'roa Hans @lof Lindgren, Appelviken, Sweden, aa-

signor, by menne assi w 1M: ents, to The lile Laval Separator Company, New York, N., Y., a corporation of New ersey lamination september ie, 193i, seminarie. esame En Sweden November S, 193@ S la7'.

The present invention relates to centrifugal separators provided with stationary pipe lines which are required to be tightly connected to the centrifuge for the supply and/or discharge of liquid. It is known in the art to supply and discharge liquid through packing boxes making e. tight joint around a'central part of the cen-.- trifugal bowl. -In connection with centrifuges in which the bowl rotates in bearings of a type that does not permit lateral displacements, i. e., fixed bearings, the pipe lines for the liquid may be connected, in known manner, by means of packing boxes, to the separator bowl through the separator frame, or through a member connected to the' separator frame. Such a construction, however, can be utilized in practice in connection only witlf centrifugal bowls rotating at a rather low speed.

Centrifuges with a rapidly revolving bowl, on the other hand, are provided with an elastic shaft, or with a rigid shaft located in bearings elastic in a radial direction. It is quite obvious that the efliciency of a tightening device which is used in connection with a rotating element which now and then vibrates strongly, such as, for instance, a separator bowl carried by elastic bearings, must be different from that of a tightening device for a non-vibratory revolving element. The radial movement of the separator bowl, measured at its centre of gravity, may amount to one millimeter or more; this being, for instance, the case when the bowl is exceeding its critical'number of revoltions. The radial movement at a packing box connected to the upper part of the bowl may be even still greater if the bowl is positioned outside the elastic bearing on the free Yend of the shaft. This is the usually employed construction for separators working at a high number of revolutions.

In order to avoid too strong a compression of the packing material when the shaft vibrates during the rotation, it has been suggested to x the packing box to an elastic element, or to an element movable in another way, which means, in some cases, has been utilized to advantage in practice. This construction, which to a certain degree permits the packing box to particpate in the oscillating movement of the bowl, has proved usable when separating liquid with good lubricating properties, the tight joint being made possible by means of pumping threads in a metal sleeve embracing the upper part of the centrifugal Y bowl. The experiments that have been made to utilize this construction in connection with such liquids as water and milk have, however, given (CE. 233ml) a negative result, owing to the difficulty of obtaining a suitable lubrication of the bearing at which the tight joint is to be established. As a matter of fact, it isimpossible to prevent the lubricant being pressed out from the contact surface between the packing box and the element against which it makes a tight joint, either in an outward or inward direction in the liquid.

It has also been suggested to use packing boxes with especially soft packing material, but this method has likewise failed owing to the fact that the packing material is pressed out by the powers of inertia from. the movable system, thus causing leakage. `The formation of leaking spots is also facilitated by the fact that, owing to the rapid rotation of the shaft, the tightening material must not be pressed too hard against the shaft by means of self-adjusting devices.

The present invention relates to a packing box between stationary pipes and rotating members of a centrifugal separator, in which the packing box comprises a tube-shaped or cylindrical element, made of an elastic material, and constructed and applied 'as hereinafter described. The force of contacgnecessary to secure a tight joint is generated by liquid pressure on the aforenamed. tube-shaped portion of the packing box. If suitable dimensions are used for the tubeshaped portion of the packing box, a completely tight joint is obtained with such vibrations as those taking place in an elastically suspended centrifugal bowl when it exceeds its critical number of revolutions.

In the drawings:

Fig. 1 is a sectional elevation of a centrifugal machine with my invention applied thereto.

Fig. 2 is an enlarged detail sectional elevation of the lower packing box.

Figs. 3, 4 and 5 are detail views, similar to Fig. 2, of modifications. g A

Fig. 6 is an enlarged detail sectional elevation of the upper packing box.

Fig. 1 illustrates a centrifugal separator provided with.A pipelines tightly connected with the same, the tight joint being secured by means of a. packing box of the type previously mentioned and hereinafter'particularly described. The liq- ,uid is, in known manner, introduced through a hollow shaft l into the centrifugal bowl 2, which is provided with an upper dome 3 having an opening in its top. Pipe lines 4 and 5 are, by means of packing boxes containing elastic collars 6, connected with the lower part of the shaft 1 andthe upper part of the bowl. The packing box illustinted in Fig. 2 is positioned between the pipe line ing chamber 12. It is preferable that the part' 7 should be pressed, by its own elasticity, against the part 9.

In another embodiment of the invention, shown in Fig. 3, the elastic collar is of inverted U-form, consisting of two legs 7 and 13, the leg 13 having a ange confined between nuts 20 and 21. By this construction there is obtained a tightening device that is self-adjusting to a still higher degree than is the device shown in Figs. 1 and 2.

The packing box can also be so constructed that no disc-shaped member or additional leg is necessary for fixing the collar. It can be, for instance, constructed in the way illustrated in Fig. 4, in which the nuts 30 and 31 have conical surfaces between which the collar is fixed.

In some cases, in order to make a tight joint against shafts which vibrate strongly, it may be necessary to provide special supports for the packing. It is then necessary to give a considerable extension in radial or axial direction respectively to the tube-shaped or the disc-shaped part, or to both of them, in order that the stresses in the collar shall not be too-great. To the tubeshaped portion 7 of the collar may be given the shape illustrated inFig. .5, the collar being in contact with the lower -part 9` of' the shaft 1 only at the free end 14. There is thus a play between \a part of the collar and the shaft'member 9.

Without special provisions, however, the liquid pressure exerted on the outside of the collar may Such support maybe a closely wound spiral spring 15, which permits the free end 14 of the collar to move in radial direction without offer- -ing any considerable resistance. By the construction shown, there is avoided an unnecessary long surface of contact, which wouldresult in great stresses in the material during the fixing, as well as in high frictional resistance.

kThe tightening devices according to Figs. 2to 5 are shown as adapted for use at the lower part of the shaft 1.

Fig. 6 illustrates a device which is essentially the same as the one in Fig. 2 and which is in.- tended to be used when the upper part of the centrifugal bowl is connected to the pipe 5. The modifications according'to Figs. 3 to 5 may also be utilized at this location.

Having now fully described my invention, what I claim and desire to protect by Letters Patent is:

1. A centrifugal machine Icomprising a .stationary pipe, a centrifugal bowl, a shaft rotating with said bowl, the shafebeing hollow and in communication with the interior of the bowl, an I elastic bearing for the shaft, a packing box forming' a chamber communicating with said pipe and into which the hollow rotary shaft extends, an elastic collar having a free end within said chamber and extending toward the stationary pipe and enclosing the shaft and adapted to be held in close-contact with the shaft by fluid pressure within said chamber, and means securing the other end of the collar to the packing box.

2. A centrifugal machine comprising a stationary pipe, a centrifugal bowl and an element rotatable therewith, a tubular elastic collar surrounding the rotatable element, and an enclosing packing box including two members ybetween which one end of said collar is coni-ined, said packing box and collar providing a chamber communicating with the xed pipe and wherein fluid pressure, acting exteriorly upon the other end of the collar, maintains it in close contact with said rotatable element.

3. A centrifugal machine comprising a stationary pipe, a centrifugal bowl and an element'rotatable therewith having a fluid passage communicating with the interior of the bowl, an elastic collar, U-shaped in longitudinal section, having an inner leg surrounding, the rotatable element and an outer leg, and means forming a chamber .4

affording fluid communication between said pipe and passage and enclosing the inner leg of said collar and securing the end of the outer leg in fixed position. t 4. A centrifugal machine comprising a stationary pipe, a centrifugal bowl and a hollow shaft rotatable therewith, an elastic collar surrounding `the shaft and having an end angularly projecting from the rotatable element, and means enclosing -the other end of the collar iis secured, and an elastic element between the rotatable element and the. part of the collar which is spaced therefrom and which is adapted to maintain the collar in a stretched condition.

6. In a centrifugal machine the combination, with a stationary frame and a bowl rotatable therein, of a hollow cylindrical extension secured to one of. said members, a liquid pressure chamber surrounding said extension and secured 'to the other of said members, and an elastic and flexible packing including a cylindrical portion surrounding said'extension and protruding into said chamber with its outer surface exposed to the pressure therein and .a flange portion attached to and extending outward fromone end of said cylindrical portion and secured to one end of said chamber.

7. In a centrifugal machine the combination, with a stationary frame and a bowl rotatable therein, of a hollow cylindrical extension secured to one of said members, a liquid pressure chamber surrounding said extension and secured to the other of said members,"` and an elastic and flexible packing including a cylindrical portion surrounding said extension and protruding into said chamber with its outer surface exposed to `the pressure therein, whereby it will be forced tightly against said extension, and a flange portion attached to and extending outward from one end of said cylindrical portion and secured to said chamber.

8. In a centrifugal machine the combination, with a stationary frame and a bowl rotatable therein, of a hollow cylindrical extension secured to one of said members, a liquid pressure cham- .ber surrounding said extension and secured to the other of said members, and an elastic and to be secured to the pressure chamber and a liquid-tight approximately cylindrical exible portion connecting the outer edge of the rst named ange portion with the inner edge of the last named ange portion.

HANS OLOF LINDGREN. 

